Magnetostatic relay



nited States PatentOfiice Patented Sept. 27, 1960 MAGNETQSTATIC RELAY Etienne Alizon, La Celle Saint-Cloud, France, assignor to Compagnie Industrielle des Telephones, Pans, France, a corporation of France Filed Nov. 15, 1956, Ser. No. 622,408

Claims. (Cl. '30788) The present invention relates to electromagnetostatic relays of the type including a saturable magnetic core, several coils coupled to the core to achieve saturation thereof, the coils including at least one energizing coil in series with a rectifier and connected in an input circuit fed by a source of alternating current, and at least one control coil fed by a source of direct current, and an output circuit for supplying rectified current.

Relays of this type may be advantageously used to replace electromagnetical relays in installations and apparatus which must exhibit certain memory characteristics and which are susceptible to respond to complex engaging conditions.

The co-pending application Serial No. 587,754, filed May 28, 1956, describes a relay of this type. The present invention constitutes an improvement over the relay described in the aforementioned co-pending application.

Accordingly, it is an object of the present invention to provide a magnetostatic relay of which the characteristic curve of the output current as a function of the control ampere-turns is essentially a straight horizontal line.

It is another object of the present invention to provide a magnetostatic relay of the type described hereinabove, which is more simple in structure, requires fewer parts and thereby is also less expensive to manufacture and assemble.

Still another important object of the present invention resides in the provision ofa magnetostatic relay of the type described hereinabove which produces a larger out.- put'current than has been attainable heretofore.

These and other objects, features and, advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawing, which shows, for purposes of illustration only, one embodiment in accordance with the present invention, and wherein:

Figure l is a schematic wiring diagram of the magnetostatic relay as shown and described in the aforementioned co-pending application Serial No. 587,754,

Figure 2 represents the characteristic curves of the relay of Figure 1,

Figure 3 is a schematic diagram of a magnetostatic relay in accordance with the present invention, and

Figure 4 shows the characteristic curve obtained with a relay in accordance with the present invention as illustrated in Figure 3.

A magnetostatic relay of the type described hereinabove and corresponding to the aforementioned co-pending application is shown in Figure 1 of the accompanying drawings, in which a saturable magnetic core is provided with an energizing coil 1 and a plurality of control coils or windings 2, 3 and 4 wound thereupon. The energizing winding or coil 1 is connected in a series circuit comprising, in the following order, a first rectifier 7, an in ductance 9, a second rectifier 11 of the same polarity as is rectifier 7, the control winding 2 on the saturable core and arranged as a feedback winding, and a load resistance 12. This series circuit may be energized from an alternating current source 14. A resistor 5 and a rectifier 6 are connected to shunt that portion of the aforementioned series circuit consisting of the coil 1 and recetifier 7, the rectifier 6 being connected in opposition to the rectifier 7. A condenser 8 is connected in shunt with that portion of the series circuit comprising inductance 9, rectifier 11, coil 2, and the load 12. Connected to the terminals g and h in shunt with the portion of the series circuit comprising the rectifier 11, the coil 2, and the load 12 is a branch circuit, consisting of a rectifier 10 and a direct current source 13, the rectifier 10 being connected to conduct current in the same direction and parallel to the rectifier 11.

In Fig. 2, the curve C is the characteristic curve of the output current I of the relay as a function of the control ampere-turns N I when the connection comprising the rectifier 10 and the source 13 is removed at points g and h. The curve C is the characteristic curve of the relay which results when the connection comprising rectifier 10 and source 13 is set up between points g and h. The current I assumes a value I which is constant but substantially lower than the values shown by the curve C In the relay according to the above-mentioned application, and as seen in Figure l, the series feed circuit through coil 1, rectifier 7, and the load 12 will, in the absence of resistor 5 and rectifier 6, produce a predetermined curve I vs. N I (not shown), and this curve may be shifted parallel to the axis of ordinance so that the curve will intersect the zero current axis at a desired negative value of N 1 The amount of displacement of the curve is a function of the value of resistance 5. Although resistance 5 and rectifier 6 tend to conduct a direct current in the direction opposite that which may pass through rectifier 7, the current through rectifier 6 is blocked by rectifier l1, and thus the curve I can never become negative in the load 12, and thus the curve I vs. N l' never drops below the axis of ordinance, as seen in Figure 2. Condenser 8 cooperates with the inductance 9 to form a simple filter network in the load circuit. The polarities of the direct current source 13 and the rectifier 10 are such that the maximum potential across resistance 12 when the load current is flowing therethrough is limited to the value of the potential of the source 13, thus achieving a flattening of the output current curve, as seen for C in Figure 2.

In referring to the curves of output current versus ampere turns, the value of the ampere turns has been considered as the algebraic sum of the ampere turns in control windings 2, 3 and 4. The windings 3 and 4 may be energized from direct current sources 15 and 16, respectively, one of which may be utilized as a biasing potential and the other as a control potential for rendering the relay active or inactive. The current in the feed-back winding 2 will, depending upon the number of turns of this winding, determine the operating points of the relay at which, on the one hand, the output current changes from zero to a. predetermined constant value as the total ampere turns are increased, and, on the other hand, the output current drops from the predetermined constant values to zero as the ampere turns are increased.

The improvement according to the invention enables to increase the energy which the relay may deliver in the output circuit.

According to the invention a condenser 17 is connected in parallel with the first rectifier 7 mentioned above.

In Fig. 3 the same reference numerals are used to designate the same elements as in Fig. 1 respectively. Reference numeral 17 designates the condenser accord ing to the invention, which replaces the connection gh.

Condenser 17 is connected in parallel with rectifier 7 to the terminals thereof and mainly acts upon the alternations of current of direction contrary to that passing through rectifier 7. The presence of condenser 17 causes a resonance phenomenon which results in the reduction of the impedance of the whole circuit and the reduction of the characteristic curve in the positive ampere turns area, which has for consequence to make the output current more constant, the curve C; of Figure 4, thus being substantially flat in this ampere turns area with the selection of a proper value for condenser 17.

In Figure 3, the inductance 9 in series with the load and the condenser 8 shunting this inductance and the load circuit form together an elementary filter. Also, as in Figure 1, the feedback winding 2 wound around the saturable magnetic core is connected in series with rectifier 11 and load resistance 12.

The rectifier 11 is connected in the output circuit in series with the load resistance 12, and its polarity is such as to carry currents in the same direction as rectifier 7. Rectifier 11 constitutes a threshold means for the output current, allowing the passage of the output current only in the positive area of the curve of Figure 4, i.e., above the ON I axis.

The characteristic curve of the relay is modified as shown by Fig. 4 in which the curve C is that without a condenser and curves C C and C correspond to increasing values of the capacity of the condenser 17. In particular for a suitable value of this capacity a characteristic curve (C which is very substantially horizontal may be obtained with a mean value of the output current which is much higher than that of the relay of Fig. 1 (curve C Fig. 2).

I claim:

1. A magnetostatic relay comprising input circuit means fed by a source of alternating current, output circuit means for supplying rectified current and including a load, a saturable magnetic core, an energizing coil coupled to said core and connected in said input circuit means, a control coil coupled to said core, a rectifier in series with said energizing coil and connected with such polarity as to pass said rectified current, a condenser connected to the terminals of said rectifier, and circuit means including a resistance and a second rectifier connected across the terminals of a circuit including said energizing coil and said first rectifier in parallel with said condenser, said condenser having the value efiecting a generally constant direct current of a value other than Zero in said load over a substantial range of control coil ampere turns.

2. A magnetostatic relay according to claim 1, further comprising filter means connected between said input circuit means and said output circuit means.

3. A magnetostatic relay comprising input circuit means fed by alternating current, output circuit means for supplying rectified current and including a load, a saturable magnetic core, an energizing coil mounted on said core and connected in said input circuit means, a control coil mounted on said core, a rectifier in series with said energizing coil, a condenser connected to the terminals of said first-mentioned rectifier and circuit means including a resistance and a second rectifier mounted to the terminals of a circuit including said energizing coil and said first rectifier in parallel with said condenser, filter means between said input circuit means and said output circuit means, and threshold means in said output circuit means.

4. A magnetostatic relay according to claim 3, further comprising a feed-back coil mounted on said core and connected in said output circuit means.

5. A magnetostatic relay comprising input circuit means fed by alternating current, output circuit means supplying rectified current and including a load, a saturable magnetic coil, an energizing coil mounted on said core and connected in said input circuit means, a control coil mounted on said core, a first rectifier in series with said energizing coil, a condenser connected to the terminals of said first rectifier, a circuit including a resistance and a second rectifier connected to the terminals of a circuit including said energizing coil and said first rectifier in parallel with said condenser, filter means between said input circuit means and said output circuit means including an inductance coil connected in said output circuit means and a second condenser connected in parallel between said input and output circuit means, threshold means in said output circuit means including a third rectifier in said output circuit means, said third rectifier being operative in the same direction as said first rectifier, and a feed-back winding mounted on said core and disposed in said output circuit means.

References Cited in the file of this patent UNITED STATES PATENTS 

